Remote control apparatus



March 24, 1936. Q BROWN}: ET AL I 2,034,708

REMOTE CONTROL APPARATUS Filed-April 28, 1934 3 Shets-Shet l B. O. BROWNE IN VEN T0R$ RE/SON a 4AM,

A TTORNEV March 24, 1936. B. o. BROWNE Er AL REMOTE CONTROL APPARATUSFiled April 28, 1954 3 Sheets-Sheet 2 L N at T E V M v M 0$ M RR "M BRam A W M M W? m March 24, 1936. B O BROWNE r AL 2,034,708

REMOTE CONTROL APPARATUS Filed April 28, 1954 3 Shets-Sheet 3 FIG. 4

8.0. BROWNE WENTORS H. MORRISON A TTORNEY Patented 24, 1936 UNITEDSTATES PATENT OFFICE REMOTE CONTROL APPARATUS Application April 28;1934, Serial No.-722,906

7 Claim.

This invention relates to remote control apparatus and particularly toapparatus for controlling the tuning of radio receivers or the like.

An object of the invention is to simplify and improve the accuracy ofapparatus for remotely controlling the angular position of an instrumentsuch as the tuning element of a radio receiver.

In a specific preferred embodiment of this invention comprising a remotecontrol for operating the tuning condensers of a radio receiver, themechanism is driven by an electric motor which is connected through acombination electromagnetic clutch and brake with a drive shaft carryinga worm. A worm gear coupled to the tuning condenser shaft is driven bythe motor. A contact arm carried by the worm gear shaft is arranged topass over and interconnect the contacts of a number of pairs of contactsspaced in an arc, corresponding to the movement of the condensers. Phesize of the contacts and contact arm are so proportioned that the arm isalways in contact with one pair of contacts. A second contact arm iscarried by the worm shaft and due to the different speeds of rotation ofthe two shafts, this contact arm will rotate through an are including anumber of contacts, as the other contact arm moves from one pair ofcontacts to another. This arrangement permits the use of two relativelysmall contact commutators or discs for providing the same degree ofaccuracy as could'otherwise be obtained only by using a very large discwhich would permit a large number of contacts to be mounted thereon.Thus, with a contact disc associated with the arm on the worm gear shafthaving fifty contacts and a contact disc, associated with the arm on theworm shaft having twelve contacts, the same effect is obtained as byusing one disc having six hundred contacts.

Operation is obtained by using a multi-point or push button switch, onepoint of which is connected to one of the contacts of the desired pairof the first contact disc, the other of the pair being connected to thatcontact of the other contact disc corresponding to the desired position.When the two contact arms are in the position to contact with thecorresponding contacts, a circuit is completed which operates theelectromagnetic relay releasing the clutch and providing anelectromagnetic braking action and at the same time operating a relaycontact to open the driving motor circult. If the control switch ismoved to a diiferent point, the electromagnetic brake will be released,the clutch engaged and the motor circuit completed causing the controlmechanism to operate until it reaches the contact point correspending tothe chosen switch position. A reversing switch, operated when thecondenser reaches the limit of its movement, provides for the properdirection of rotation of the driving motor.

Since it is imperative that the tuning condenser always stop at exactlythe same position for any one setting of the control switch no backlashbetween the worm and worm wheel can be allowed. Regardless of thedirection in which the worm wheel is being moved the same side of theteeth 18 or the wheel must always be in contact with the worm. This isbrought about by the use of a spiral spring which always tends to rotatethe worm wheel in one direction. Thus, for rotation in one direction themotor drives the worm wheel l5 against the action or the spring and mthe other direction the spring drives the worm wheel and tuningcondenser while the motor-driven worm merely acts as a release mechanismto control the rate of motion. a

The motor control mechanism is simplified by combining the brake, clutchand motor control switch in one electromagnetic relay structure.

The invention can be more readily understood by reference to thefollowing detailed description 25 in connection with the drawings whichshow one embodiment of the invention in a remote control unit designedfor operating the tuning condenser of a radio receiver:

Fig. 1 is a simplified schematic showing of the so mechanical andelectrical arrangements of the complete apparatus.

Fig. 2 is a front elevation of the operating unit partly in section; and

Figs. 3 and 4 are end elevations partly in section 35 taken along thelines 33 and 4-4, respectively, of Fig. 2.

Mechanical construction The apparatus forming the operating unit is 40mounted on a framework comprising a front plate 4i and a rear plate 42spaced by the six posts 43 to which are secured mounting plates 44, 45and 46. The entire assembly is protected by a cover 4?.

A shaft 5 is coupled to the shaft 6 of the tuning 4 condenser (notshown) of a radio receiver. The shaft 5 carries a worm wheel 1 whichmeshes with a worm 8 carried by a shaft 9 journaled in the mountingplates 44 and IS. The shaft 9 is driven 50 by an electrical motor l2through the gear train I I and the clutch III.

A spring l3 holds the clutch in engagement by the action it exerts inclamping the last gear 18 of the gear train I I between the cork facedplates 5 magnet not only acts to release the clutchbut the attraction ofthe plate l5 also produces a braking action stopping the shaft 9 andconsequently the tuning mechanism. A pin l8 extends through a hole inone pole piece of the electromagnet l1 and is operated by the disc l5 toopen the contacts IQ for controlling the motor circuit.

The position at which the worm wheel 1 and thus the tuning condenserstops is controlled by two multi-contact switches or commutators 2|! and30 and a control switch 40 which is located at the control position. Thecomplete system including the electrical connections as shown typicallyin Fig. 1 provides for stopping the tuning condenser at any one of sixhundred equally spaced positions around the complete one hundred andeighty degree are of motion of the condenser as will be described indetail.

The switch comprises fifty pairs of contacts 2l-22 mounted in the plate4| in a one hundred and eighty degree arc corresponding to the movementof the tuning condenser with brushes 2d and riding over them. Spacedbetween adjacent pairs of contacts 2|22 are pins 23 which are of similarconstruction to the contacts and provide a surface on which the brushes24 and 25 ride. An arm 25 of insulating material fixed to the shaft 5carries the brushes 24 and 25 which are electrically connected togetherso as to cross-connect one pair of the contacts 2|--22 in each position.The contacts 2l-22 and the brushes 24 and 25 are so proportioned thatthe brushes are always in contact with one or another of the pairs ofcontacts.

The switch has twenty-four contacts 3| mounted in the plate 44. A blockof insulating material 32 fixed to the shaft 9 carries a brush typecontactor 33 which slides over the contacts 3|. A second brush 34 alsocarried by the block 32 and interconnected to the brush 33 by the strap36 makes continuous contact with a ring mounted on the plate 44.

The reduction ratio between the speed of the worm 8 and the worm wheel Iwhich drives the brushes of the switch 20 is such that the brush 33makes one complete revolution while the brushes 24 and 25 are passingover two of the contact pairs 2l-22. In other words, the brush 23 passesover twelve of the contacts 3| for each contact pair 2|22 coveredby thebrushes 24 and 25. An interconnection between the contacts of theswitches 20 and 3|] controls the stopping of the condenser shaft as willbe described later.

Since the exact position of the operating shaft 5 is determined by theswitch 30 and since it is imperative that the condenser always stop atexactly the same position for any one setting, no

back lash between the worm 8 and the worm wheel I can be permitted. Thisresult is accomplished by the use of the spiral spring 5| to keep thesame side of the teeth of the worm wheel 1 in contact with the worm 8regardless of the direction of rotation. This spring 5| has one endattached to the shaft 5 and the other to the plate 45 so that it alwaystends to rotate the worm wheel 1 in one direction. Thus, for rotation inone direction the motor drives the worm wheel 1 against the action ofthe spring 5| and in the other direction the spring 5| drives the wormwheel '|-the motor-driven worm merely acting as a release mechanism tocontrol the rate of motion and the stopping position. A spiral spring 52and thrust bearings 53 and 54 take up the force exerted on the shaftfl.

A reversing switch 55 is provided for reversing the direction ofrotation of the motor l2 when the shaft 5 reaches either limitingposition of the tuning condenser. The switch 55 is operated by theaction of the shoulder 51 or 58 of the arm 25 on the operating handle56.

Operation The action of the apparatus may be readily understood from adescription of the process of setting up a tuning position (whenattached to a radio receiver). With the cover 41 removed and the motorshut off and switch 50 open, the block 32 may be used as a knobpermitting the tuning condenser to be tuned by hand. The knob is turneduntil the desired station is properly tuned in. A connection M (Fig. 1)is then made from the contact 49 of the operating switch which it isdesired to use for this particular station to the contact 22 of the pair2 |22 upon which the brushes 24 and 25 are resting. A second connection12 is made from the contact 2| of the same pair to that one of thecontacts 3| upon which brush 33 is resting. A circuit is thus formedfrom the grounded terminal of battery 10 through the arm 48 and contact49, connection 1|, contact 22, switch arms 24 and 25, contact 2|,connection 12, contact 3|, brushes 33 and 44, ring 35, connection 13 andthe coil of electromagnet back to battery 10. This circuit will operatethe electromagnet l1 attracting the plate l5 to release the clutch l0and lock the shaft 9 by the braking action and open the motor circuit atthe contact l9.

If the arm 49 of the control switch is now moved to another contact, thecircuit through the switches 20 and 30 to the electromagnet I1 isopened, so that the clutch will engage and the motor circuit be closedat contact |9 (the shutofi switch 50 having been previously closed). Themotor l2 will then drive the unit until another set of similarlyestablished connections closes the circuit and releases the clutch.

In order to avoid confusion only one circuit is shown in the diagram, itbeing understood that there will be as many similar circuits as thereare desired tuning positions.

The direction of rotation of the apparatus is reversed when the shaft 5reaches either limiting position of the tuning condenser by the actionof the shoulders 51 or 58 in operating the reversing switch 55.

While the switch 4|] is shown as a multi-contact switch, it may be amulti-button switch of the locking type, or if it is desired to reducethe number of connections between the operating unit and the controlposition, a selector may be used in place of the switch 40 and operatedfrom a distance by a dial of the telephone type.

What is claimed is:

1. A remote control for a radio receiver or the like comprising aninstrument shaft, a main selector having a contact arm and a pluralityof pairs of contacts so arranged that the arm will always be in contactwith a pair of contacts to connect them together, an auxiliary selectorcomprising a contact arm and a plurality of contacts, gear meansinterconnecting said contact arms so that the second contact arm coversa number of contacts while the first contact arm is on one pair ofcontacts, and a plurality of control circuits each interconnecting apair of contacts of the main selector and a predetermined contact of thesecond selector to stop the instrument shaft at a definite position.

2. In a remote control system for a radio re ceiver or the like havingan instrument shaft to be controlled, a driving motor, a clutch, a driveshaft arranged to be driven by said motor through said clutch, a wormcarried by said drive shaft, a second shaft connected to said instrumentshaft, a worm wheel carried by said second shaft and meshing with saidworm, a first multi-contact switch having a switch arm carried by saidsecond shaft, and a plurality of contacts, said arm being arranged tocontact one of said contacts for each position, a second multi-contactswitch having a plurality of contacts and a switch arm carried by thedrive shaft so that the arm will pass over a number of contacts as theswitch arm of the first multi-contact switch passes over each contact,and a control circuit for each desired posit-ion of the instrument shaftarranged to release the olutch when the two contact arms are on therespective contacts corresponding to the desired position of theinstrument shaft. I

3. In a remote control system for a radio receiver or the like having aninstrument shaft to be controlled, a driving motor, a clutch, a driveshaft arranged to be driven by said motor through said clutch, a brakefor said drive shaft, a worm carried by said drive shaft, a second shaftconnected to said instrument shaft, a worm wheel carried by said secondshaft and meshing with said worm, a first multi-contact switch having aswitch arm carried by said second shaft and a plurality of contacts,said arm being arranged to contact one of said contacts for eachposition, a second multi-contact switch having a plurality of contactsand a switch arm carried by the drive shaft so that the arms pass over anumber of contacts as the switch arm of the first multicontact switchpasses over each contact, and a control circuit for each desiredposition of the -instrument shaft arranged to release the clutch andoperate the brake when the contact arms are on the respective contactscorresponding to the desired position.

4. In a remote control system for a radio re-- ceiver or the like havingan instrument shaft to be controlled, a driving motor, a drive shaftarranged to be driven by said motor, a worm carried by said drive shaft,a second shaft connected to said instrument shaft, a worm wheel carriedby said second shaft and meshing with said worm, a first multi-contactswitch having a switch arm carried by said second shaft, and a pluralityof pairs of contacts so arranged that said switch arm is always incontact with one of said pairs of contacts to interconnect such pair ofcontacts, a second multi-contact switch having a plurality of contactsand a switch arm carried by the drive shaft-so that the arm will passover a number of contacts as the switch arm of the first multi-contactswitch passes over each pair of contacts, and a control circuit for eachof a plurality of desired positions of the instrument shaft including inseries one of said pairs of contacts of said first multi-contact switchand a contact of said second multi-contact switch and arranged to stopthe rotation of the instrument shaft when the circuit is completed.

5. In a remote control system for a radio receiver or the like having aninstrument shaft to be controlled, a driving motor, a combinationelectromagnetic clutch and brake, a drive shaft driven by said motorthrough said clutch, a worm carried by said drive shaft, a second shaftconnected to said instrument shaft, a worm wheel carried by said secondshaft and meshing with said worm, a first multi-contact switch having aswitch arm carried by said second shaft, and a plurality of pairs ofcontacts, said arm being arranged to interconnect a pair of contacts ineach position, a second multi-contact switch having a plurality ofcontacts and a switch arm carried by the drive shaft so that the armwill pass over a number of contacts as the switch arm of thefirst-multi-contact switch passes over.

each pair of contacts, and a control circuit comprising a series circuitincluding a control element, one contact of a pair of contacts of thefirst switch, a second contact of said pair, and a contact of saidsecond switch and arranged when completed to operate the combinationbrake and clutch to release the clutch and apply the brake to the driveshaft.

6. A combination according to claim 5 and a spring attached to saidsecond shaft so that for rotation in one direction the worm turns theworm wheel against the action of the spring and for rotation in theother direction the spring drives the worm wheel.

7. In a remote control for an instrument shaft designed to be driventhrough an arc of less than three hundred and sixty degrees, a wormwheel carried by said shaft, a drive shaft, a worm carried by said driveshaft and meshing with said worm wheel, means carried by said driveshaft for determining a desired position of said instrument shaft, and aspring attached to said instrument shaft so that for rotation inonedirection the motor turns the worm wheel against the action of thespring and for rotation in the other direction the spring drives theworm wheel, and means for reversing the direction of rotation of saidmotor when said instrument shaft reaches either limit of its arc ofrotation.

BENNIE O. BROWNE. HOWARD MORRISON.

